183 research outputs found
Effective Rheology of Bubbles Moving in a Capillary Tube
We calculate the average volumetric flux versus pressure drop of bubbles
moving in a single capillary tube with varying diameter, finding a square-root
relation from mapping the flow equations onto that of a driven overdamped
pendulum. The calculation is based on a derivation of the equation of motion of
a bubble train from considering the capillary forces and the entropy production
associated with the viscous flow. We also calculate the configurational
probability of the positions of the bubbles.Comment: 4 pages, 1 figur
The number of tree species on Earth
One of the most fundamental questions in ecology is how many species inhabit the Earth. However, due to massive logistical and financial challenges and taxonomic difficulties connected to the species concept definition, the global numbers of species, including those of important and well-studied life forms such as trees, still remain largely unknown. Here, based on global ground-sourced data, we estimate the total tree species richness at global, continental, and biome levels. Our results indicate that there are ∼73,000 tree species globally, among which ∼9,000 tree species are yet to be discovered. Roughly 40% of undiscovered tree species are in South America. Moreover, almost one-third of all tree species to be discovered may be rare, with very low populations and limited spatial distribution (likely in remote tropical lowlands and mountains). These findings highlight the vulnerability of global forest biodiversity to anthropogenic changes in land use and climate, which disproportionately threaten rare species and thus, global tree richness
Tree mode of death and mortality risk factors across Amazon forests
The carbon sink capacity of tropical forests is substantially affected by tree mortality. However, the main drivers of tropical tree death remain largely unknown. Here we present a pan-Amazonian assessment of how and why trees die, analysing over 120,000 trees representing > 3800 species from 189 long-term RAINFOR forest plots. While tree mortality rates vary greatly Amazon-wide, on average trees are as likely to die standing as they are broken or uprooted—modes of death with different ecological consequences. Species-level growth rate is the single most important predictor of tree death in Amazonia, with faster-growing species being at higher risk. Within species, however, the slowest-growing trees are at greatest risk while the effect of tree size varies across the basin. In the driest Amazonian region species-level bioclimatic distributional patterns also predict the risk of death, suggesting that these forests are experiencing climatic conditions beyond their adaptative limits. These results provide not only a holistic pan-Amazonian picture of tree death but large-scale evidence for the overarching importance of the growth–survival trade-off in driving tropical tree mortality
Molecular gated nanoporous anodic alumina for the detection of cocaine
[EN] We present herein the use of nanoporous anodic alumina (NAA) as a suitable support to implement
molecular gates for sensing applications. In our design, a NAA support is loaded with a fluorescent
reporter (rhodamine B) and functionalized with a short single-stranded DNA. Then pores are blocked
by the subsequent hybridisation of a specific cocaine aptamer. The response of the gated material
was studied in aqueous solution. In a typical experiment, the support was immersed in hybridisation
buffer solution in the absence or presence of cocaine. At certain times, the release of rhodamine B from
pore voids was measured by fluorescence spectroscopy. The capped NAA support showed poor cargo
delivery, but presence of cocaine in the solution selectively induced rhodamine B release. By this simple
procedure a limit of detection as low as 5 × 10−7 M was calculated for cocaine. The gated NAA was
successfully applied to detect cocaine in saliva samples and the possible re-use of the nanostructures
was assessed. Based on these results, we believe that NAA could be a suitable support to prepare
optical gated probes with a synergic combination of the favourable features of selected gated sensing
systems and NAA.We thank Projects MAT2015-64139-C4-1-R and TEC2015-71324-R (MINECO/FEDER), the Catalan Government (Project 2014 SGR 1344), the ICREA (ICREA2014 Academia Award) and the Generalitat Valenciana (Project PROMETEOII/2014/047) for support. We also thank to the Agencia Espanola del Medicamento y Productos Sanitarios for its concessions. A.R. thanks the UPV for her predoctoral fellowship. The authors also thank the Electron Microscopy Service at UPV for support.Ribes, À.; Xifre Perez, E.; Aznar, E.; Sancenón Galarza, F.; Pardo Vicente, MT.; Marsal, LF.; Martínez-Máñez, R. (2016). Molecular gated nanoporous anodic alumina for the detection of cocaine. Scientific Reports. 6. https://doi.org/10.1038/srep38649S386496Nadrah, P., Planinšek, O. & Gaberšček, M. Stimulus-responsive Mesoporous Silica Particles. J. Mater. Sci. 49, 481–495 (2014).Baeza, A., Colilla, M. & Vallet-Regí, M. Advances in Mesoporous Silica Nanoparticles for Targeted Stimuli-Responsive Drug Delivery. Expert Opin. 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Bioresponsive Controlled Release Using Mesoporous Silica Nanoparticles Capped with Aptamer-Based Molecular Gate. J. Am. Chem. Soc. 133, 1278–1281 (2011).Özalp, V. C., Pinto, A., Nikulina, E., Chulivin, A. & Schäfer, T. In Situ Monitoring of DNA-Aptavalve Gating Function on Mesoporous Silica Nanoparticles. Part. Part. Sys. Charact. 31, 161–167 (2014).Choi, Y. L., Jaworski, J., Seo, M. L., Lee, S. J. & Jung, J. H. Controlled release using mesoporous silica nanoparticles functionalized with 18-crown-6 derivative. J. Mater. Chem. 21, 7882–7885 (2011).Zhang, Z., Wang, F., Balogh, D. & Willner, I. pH-controlled release of substrates from mesoporous SiO2 nanoparticles gated by metal ion-dependent DNAzymes. J. Mater. Chem. B. 2, 4449–4455 (2014).Fu, L. et al. Portable and Quantitative Monitoring of Heavy Metal Ions Using Dnazyme-Capped Mesoporous Silica Nanoparticles with a Glucometer Readout. J. Mater. Chem. B. 1, 6123–6128 (2013).Díez, P. et al. Toward the Design of Smart Delivery Systems Controlled by Integrated Enzyme-Based Biocomputing Ensembles. J. Am. Chem. Soc. 136, 9116–9123 (2014).Tang, D. et al. Low-Cost and Highly Sensitive lmmunosensing Platform for Aflatoxins Using One-Step Competitive Displacement Reaction Mode and Portable Glucometer-Based Detection. Anal. Chem. 86, 11451–11458 (2014).Hou, L., Zhu, C., Wu, X., Chen, G. & Tang, D. Bioresponsive Controlled Release from Mesoporous Silica Nanocontainers with Glucometer Readout. Chem. Commun. 50, 1441–1443 (2014).Chen, Z. et al. Stimulus-response mesoporous silica nanoparticle-based chemiluminescence biosensor for cocaine determination. Biosens. Bioelectro. 75, 8–14 (2016).Pascual, L. L. et al. Oligonucleotide-Capped Mesoporous Silica Nanoparticles as DNA-Responsive Dye Delivery Systems for Genomic DNA Detection. Chem. Commun. 51, 1414–1416 (2015).Qian, R., Ding, I. & Ju, H. Switchable Fluorescent Imaging of Intracellular Telomerase Activity Using Telomerase-Responsive Mesoporous Silica Nanoparticle. J. Am. Chem. Soc. 135, 13282–13285 (2013).Ren, K., Wu, J., Zhang, Y., Yan, F. & Ju, H. Proximity Hybridization Regulated DNA Biogate for Sensitive Electrochemical Immunoassay. Anal. Chem. 86, 7494–7499 (2014).Chen, Y., Santos, A., Wang, Y., Wang, C. & Losic, D. Biomimetic Nanoporous Anodic Alumina Distributed Bragg Reflectors in the Form of Films and Microsized Particles for Sensing Applications. ACS Appl Mater Interfaces. 7, 19816–19824 (2015).Aw, M. S., Bariana, M. & Losic, D. In Nanoporous Alumina. Fabrication, Structure, Properties and Applications (ed. Losic, D., Santos, A. ) 319–354 (Springer International Publishing, 2015).Urteaga, R. & Berli, C. L. In Nanoporous Alumina. Fabrication, Structure, Properties and Applications (ed. Losic, D., Santos, A. ) 249–269 (Springer International Publishing, 2015).Vojkuvka, L., Marsal, L. F., Ferré-Borrull, J., Formentin, P. & Pallarés, J. Self-Ordered Porous Alumina Membranes with Large Lattice Constant Fabricated by Hard Anodization. Superlattices Microstruct. 44, 577–582 (2008).De la Escosura-Muñiz, A. & Merkoçi, A. Nanochannels Preparation and Application in Biosensing. ACS Nano. 6, 7556–7583 (2012).Kumeria, T. et al. Nanoporous Anodic Alumina Rugate Filters for Sensing of Ionic Mercury: Toward Environmental Point-of-Analysis Systems. ACS Appl. Mater. Interfaces. 6, 12971−12978 (2014).Santos, A., Kumeria, T. & Losic, D. Nanoporous Anodic Alumina: A Versatile Platform for Optical Biosensors. Materials. 7, 4297–4320 (2014).Ferré-Borrull, J., Pallarès, J., Macías, G. & Marsal, L. F. Nanostructural Engineering of Nanoporous Anodic Alumina for Biosensing Applications. Materials. 7, 5225–5253 (2014).Gong, D., Yadavalli, V., Paulose, M., Pishko, M. & Grimes, C. A. Controlled Molecular Release Using Nanoporous Alumina Capsules. 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Group 9 Organometallic Compounds for Therapeutic and Bioanalytical Applications. Acc. Chem. Res. 47, 3614–3631 (2014).Wanga, G., Zhua, Y., Chena, L. & Zhanga, X. Photoinduced electron transfer (PET) based label-free aptasensor for platelet-derived growth factor-BB and its logic gate application. Biosens. Bioelectron. 63, 552–557 (2015).Laptenko, O. et al. The p53 C Terminus Controls Site-Specific DNA Binding and Promotes Structural Changes within the Central DNA Binding Domain. Molec. Cell. 57, 1034–1046 (2015).McKeague, M. & DeRosa, M. C. Challenges and Opportunities for Small Molecule Aptamer Development. J. Nucleic Acids. 2012, 1–20 (2012).McKeague, M. et al. Analysis of In Vitro Aptamer Selection Parameters, J. Mol. Evol. 81, 150–161 (2015).Ellington, A. D. & Szostak, J. W. In vitro selection of RNA molecules that bind specific ligands. Nature. 346, 818–822 (1990).Wochner, A. et al. A DNA aptamer with high affinity and specificity for therapeutic anthracyclines. Anal Biochem. 373, 34–42 (2008).Song, K. M., Jeong, E., Jeon, W., Cho, M. & Ban, C. Aptasensor for ampicillin using gold nanoparticle based dual fluorescence-colorimetric methods. Anal. Bioanal. Chem. 402, 2153–2161 (2012).Özalp, V. C. & Schäfer, T. Aptamer-Based Switchable Nanovalves for Stimuli-Responsive Drug Delivery. Chem. Eur. J. 17, 9893–9896 (2011).Stojanovic, M. N., de Prada, P. & Landry, D. W. Aptamer-Based Folding Fluorescent Sensor for Cocaine. J. Am. Chem Soc. 123, 4928–4931 (2001).Wen, Y. et al. DNA-based intelligent logic controlled release systems. Chem. Commun. 48, 8410–8412 (2012).Chen, L. et al. Programmable DNA switch for bioresponsive controlled release. J. Mater. Chem. 21, 13811–13816 (2011).Oroval, M. et al. An aptamer-gated silica mesoporous material for thrombin detection. Chem. Commun. 49, 5480–5482 (2013).Barroso, M., Gallardo, E. & Queiroz, J. A. Bioanalytical methods for the determination of cocaine and metabolites in human biological samples. 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Chem. 37, 3998 (2013).Marsal, L. F., Vojkuvka, L., Formentin, P., Pallarés, J. & Ferré-Borrull, J. Fabrication and Optical Characterization of Nanoporous Alumina Films Annealed at Different Temperatures. Optical Mater. 31, 860–864 (2009).Bosker, W. M. & Huestis, M. A. Oral Fluid Testing for Drugs of Abuse. Clinical Chem. 55, 1910–1931 (2009).Kolbrich, E. A. et al. Cozart® RapiScan Oral Fluid Drug Testing System: An Evaluation of Sensitivity, Specificity, and Efficiency for Cocaine Detection Compared with ELISA and GC-MS Following Controlled Cocaine Administration. J. Anal Toxicol. 27, 407–411 (2003).Cooper, G., Wilson, L., Reid, C., Main, L. & Hand, C. Evaluation of the Cozart® RapiScan drug test system for opiates and cocaine in oral fluid. Forensic Sci. Int. 150, 239–243 (2005).Chang, Y. H. et al. Cocaine detection by a mid-infrared waveguide integrated with a microfluidic chip. Lab Chip. 12, 3020–3023 (2012).Walczak, R. et al. Toward Portable Instrumentation for Quantitative Cocaine Detection with Lab-on-a-Paper and Hybrid Optical Readout. Procedia Chem. 1, 999–1002 (2009).Qiu, L. et al. A novel label-free fluorescence aptamer-based sensor method for cocaine detection based on isothermal circular strand-displacement amplification and graphene oxide absorption. New J. Chem. 37, 3998–4003 (2013)
Genetic characterization of cotton landraces found in the Paraíba and Rio Grande do Norte states
Alignment of the ALICE Inner Tracking System with cosmic-ray tracks
37 pages, 15 figures, revised version, accepted by JINSTALICE (A Large Ion Collider Experiment) is the LHC (Large Hadron Collider) experiment devoted to investigating the strongly interacting matter created in nucleus-nucleus collisions at the LHC energies. The ALICE ITS, Inner Tracking System, consists of six cylindrical layers of silicon detectors with three different technologies; in the outward direction: two layers of pixel detectors, two layers each of drift, and strip detectors. The number of parameters to be determined in the spatial alignment of the 2198 sensor modules of the ITS is about 13,000. The target alignment precision is well below 10 micron in some cases (pixels). The sources of alignment information include survey measurements, and the reconstructed tracks from cosmic rays and from proton-proton collisions. The main track-based alignment method uses the Millepede global approach. An iterative local method was developed and used as well. We present the results obtained for the ITS alignment using about 10^5 charged tracks from cosmic rays that have been collected during summer 2008, with the ALICE solenoidal magnet switched off.Peer reviewe
Nutritional reserves of Vochysiaceae seeds: chemical diversity and potential economic uses
Knowledge of healthcare professionals regarding the vertical transmission of syphilis in Fortaleza -CE, Brazil
Pan-cancer analysis of whole genomes
Cancer is driven by genetic change, and the advent of massively parallel sequencing has enabled systematic documentation of this variation at the whole-genome scale(1-3). Here we report the integrative analysis of 2,658 whole-cancer genomes and their matching normal tissues across 38 tumour types from the Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium of the International Cancer Genome Consortium (ICGC) and The Cancer Genome Atlas (TCGA). We describe the generation of the PCAWG resource, facilitated by international data sharing using compute clouds. On average, cancer genomes contained 4-5 driver mutations when combining coding and non-coding genomic elements; however, in around 5% of cases no drivers were identified, suggesting that cancer driver discovery is not yet complete. Chromothripsis, in which many clustered structural variants arise in a single catastrophic event, is frequently an early event in tumour evolution; in acral melanoma, for example, these events precede most somatic point mutations and affect several cancer-associated genes simultaneously. Cancers with abnormal telomere maintenance often originate from tissues with low replicative activity and show several mechanisms of preventing telomere attrition to critical levels. Common and rare germline variants affect patterns of somatic mutation, including point mutations, structural variants and somatic retrotransposition. A collection of papers from the PCAWG Consortium describes non-coding mutations that drive cancer beyond those in the TERT promoter(4); identifies new signatures of mutational processes that cause base substitutions, small insertions and deletions and structural variation(5,6); analyses timings and patterns of tumour evolution(7); describes the diverse transcriptional consequences of somatic mutation on splicing, expression levels, fusion genes and promoter activity(8,9); and evaluates a range of more-specialized features of cancer genomes(8,10-18).Peer reviewe
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